Nano zerovalent iron (nZVI) is one of the most broadly applied nanomaterials in the fields of groundwater remediation which benefits from its high reactivity for pollutants. However, its successful application faces challenges due to its tendency to agglomerate or form passive (oxy)hydroxide corrosion. With the emerging microplastics (MPs) pollution in groundwater system in recent years and considerable data vacancy on its potential physicochemical and ecological effects, it complicates the situation for groundwater remediation. Hereby, we investigated the effects on metal removal by nZVI in groundwater in the presence of various MPs. The removal capacity of Cu (II), Cr (VI), Pb (II) and Zn (II) by nZVI was found to be inhibited to different degrees in the presence of MPs. Desorption of metallic ions was observed dependent on various metal species, with the highest desorption rate in Zn (II). Amongst all MPs investigated, including polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC), PVC poses the most adverse impact on metal desorption, attributing to its promotion of nZVI aging through electrostatic attraction. This study focused on the impact of MPs to metal remediation, beyond the general aspect of MPs hazard such as its toxic effects or delivery of contaminants. Moreover, groundwater was investigated to make a useful supplement to the research of MPs which primarily focuses on surface water.

中文翻译：

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地下水中存在微塑料时纳米零价铁修复重金属：抑制和诱导促进老化效应

纳米零价铁（nZVI）是地下水修复领域应用最广泛的纳米材料之一，得益于其对污染物的高反应活性。然而，由于其容易结块或形成被动（氧）氢氧化物腐蚀，其成功应用面临挑战。近年来地下水系统中微塑料（MPs）污染的出现，以及其潜在物理化学和生态影响的大量数据缺乏，使得地下水修复的情况变得更加复杂。因此，我们研究了在各种 MP 存在的情况下 nZVI 对地下水中金属去除的影响。研究发现，在MPs存在下，nZVI对Cu(II)、Cr(VI)、Pb(II)和Zn(II)的去除能力受到不同程度的抑制。观察到金属离子的解吸取决于各种金属种类，其中 Zn (II) 的解吸率最高。在所有研究的MP中，包括聚苯乙烯（PS）、聚乙烯（PE）、聚对苯二甲酸乙二醇酯（PET）和聚氯乙烯（PVC），PVC对金属解吸的不利影响最大，归因于其通过静电吸引促进nZVI老化。这项研究的重点是 MP 对金属修复的影响，超出了 MP 危害的一般方面，例如其毒性作用或污染物的输送。此外，对地下水的研究也是对以地表水为主的MPs研究的有益补充。